Here is a clear map of Korea, made by a Japanese named Sewaki (瀬脇壽人) with the help of a Korean named Kim In-seung (金麟昇), who told Sewaki how to pronounce the Korean placenames. [Click the map to enlarge.]
The date of the map is unknown, but it may have been made sometime between 1860 and 1870. (Sewaki's daughter was the wife of the famous medical doctor Takagi Kanehiro, who established the Jikei Medical School in Tokyo in 1881.)
This map shows Usando (于山島) to the west of Ulleungdo (鬱陵島), which supports the claim that Usando was not Liancourt rocks (Dokdo/Takeshima) since Liancourt Rocks is southeast of Ulleungdo. Even though the mapmaker put a great deal of effort into showing all the small islands around Korea, Liancourt Rocks was not shown on the map, which is more evidence that Koreans did not know about the rocks at the time or, at least, did not consider them part of Korean territory.
(There is Japanese writing at Ulleungdo saying that it is called "Takeshima" in Japan.)